Morphopathological and immunohistochemical characteristics of submandibular fibroma in a Horse

摘要

A 12 year old male Darreh-shouri horse was referred with a slow growing submandibular mass. Grossly, the mass was solitary, well circumscribed, round and of firm consistency. Microscopically, densely packed irregular collagenous connective tissue withmany fibrocytes and fibroblasts were observed. There were rare mitotic figures. Adnexal structures were displaced and compressed peripherally. No malignancy and inflammatory reaction was present in the tumoral tissue. Abundant bundles of blue collagen fibers were seen in the tumor sections stained by Masson’s trichrome. In immunohistochemical staining, positive diffuse expression of CD34 was observed. According to the histopathological, histochemical and immunohistochemical findings, the mass was diagnosed as fibroma.